The present invention generally relates to dental hygiene. More specifically, the present invention relates to improving the dental hygiene of pets. It relates also a polymer composition having a continuous phase and a discontinuous phase, and which may find application in improving pet dental hygiene.
It is of course known that there are many different products for improving the health and well-being of animals, especially pets. These products run a vast array including products designed to improve dental hygiene in pets.
It is known that poor dental health is very common in animals, including pets such as dogs and cats. Poor dental hygiene can result in periodontal disease. Periodontal disease is one of the most commonly treated disease by veterinarians in the United States.
The long term impact of poor dental health can be devastating to an animal. Poor dental health is thought to be a contributing factor in the deaths of dogs, cats, and other manuals. In pets, it has been linked with serious diseases of the heart, liver, kidney, and other internal organs. Indeed, one study demonstrated that every dog with periodontal disease had pathological changes in the heart, liver, and kidneys.
Most periodontal disease starts with the formation of a film of a soft amorphous material called plaque, consisting primarily of oral bacteria, bacterial byproducts, and oral debris. This film typically covers both the exposed tooth surface and the area lying under the gum line, the gingival cavity. Through the deposition of calcium and other mineral salts, this layer of plaque hardens and develops into tartar. Although tartar is hard, it is also porous and adheres to the tooth surface. It appears to be progressively deposited in layers and provides a rough surface onto which more plaque is deposited. As tartar builds up, a broad range of microbes can attach. The byproducts of metabolism from these bacteria cause inflammation of local tissues including those surrounding the gingival cavity. This ultimately leads to periodontal disease. The earliest stage is gingivitis, characterized by inflammation of the gums. As periodontal disease progresses, gingivitis becomes periodontitis, with inflammation extending into the connective tissues surrounding the tooth. Through gingivitis and periodontitis, it is thought that harmful bacteria enter into the blood stream and ultimately lodge in the heart and other internal organs.
It has been found that the sides of the teeth facing the cheeks, i.e. located in the buccal cavity, have a greater incidence of gingivitis and plaque/tartar build-up than the sides of the teeth facing the tongue, i.e., the lingual side. It has also been found that the rear teeth, i.e., the pre-molars and molars; more rapidly develop plaque and tartar than the front teeth.
A variety of development efforts have focused on cleaning teeth and improving dental hygiene in animals. One simple method for removing plaque in pets is for the pet owner to brush his pet's teeth regularly. Unfortunately, few pet owners are willing or able to maintain this level of home care.
Therefore, efforts have focused on providing products that clean the teeth of pets while being chewed. There are a number of such products that claim to help clean the teeth of pets. However, few are totally effective and many suffer from a variety of disadvantages.
One of the problems of such products is that some of them are not edible. Hence, once the products are chewed or broken up by the pets and swallowed they cause digestive problems in the animals. Another problem with some products is that they have limited efficacy in cleaning the molars and pre-molars. These are the teeth where typically tartar build up is heaviest and also which are the most difficult teeth for an owner to clean with a toothbrush.
Further, many such products do not always clean the crevices of these teeth. Moreover, many such products are ineffective in cleaning the areas underneath the gums. Still further, many such products are not effective in promoting cleaning of the surfaces of the teeth that are located in the rear of the buccal cavity. If the product is poorly designed, then, during chewing, little of the product will actually enter the rear buccal cavity, thus leading to reduced abrasive action and limited cleaning of the tooth surface.
A further problem is that many of these products are ineffective in removing existing tartar. Because tartar is so hard, attempting to remove tartar by the simple abrading action caused by chewing may not be effective in reducing the tartar.
Some such products have oral care additives that are designed to inhibit the formation of tartar. A problem with some of these products is that they do not necessarily function as desired. In this regard, the efficacy of these agents disappears when the product is swallowed or other food is eaten by the animal. In a similar vein, some of these products are unstable and their texture changes with time, losing their cleansing properties.
U.S. Pat. No. 6,110,521 describes a wheat and casein dog chew having a texture that can be modified by the dog minder by subjecting the chew to microwave radiation, causing expansion and rendering it more easy to chew. To enable the expansion under microwave heating, the product has to have a moisture content of 10% to 14% by weight.
PCT patent publication number WO 00/13521 describes a chewable toy for a pet that has a protein based thermoplastic composition and can be fashioned into the shape of a bone. Applicants believe that the products described therein have limited dental efficacy. The application suggests that simply producing a product that “mimics natural animal bone shapes” and which allows “pets to softly penetrate the chewable toy” promotes clean healthy teeth and fresh breath. But, such a product will not necessarily promote effective teeth cleaning, especially in the difficult areas such the rear teeth, e.g., the molars, under the gum lines and in the area opposite the cheeks, i.e., the buccal cavity. These are the areas where plaque accumulation can rapidly develop into gingivitis and pathogenic bacteria enter the blood stream with potentially harmful consequences.
European patent application number EP 0 552 897 A1 discloses an edible animal chew product with a flexible cellular matrix containing cellulosic fibers e.g. 20 to 50% corn cobs and oral care additives. However, a difficulty with the product of this disclosure is that corncob and such cellulosic materials are unnatural to a pet animal's diet and can contribute to diarrhea and increased fecal volume. This is the opposite of the desires of many owners, who prefer not to have increased fecal volume from their pets. Another disadvantage of the above products is that they rely on the teeth being initially cleaned by dental prophylaxis by a veterinarian. Few owners regularly have a veterinarian perform dental prophylaxis.
A common failure of the prior art is that it neglects the bite force exerted by the teeth and the biting behavior of the target animals. If the bite resistance is too high, then the teeth will not evenly penetrate the product and there will be little opportunity for the product to push against the gums and clean in critical areas. Conversely, if the bite resistance is too low then the dog will rapidly bite through the product and swallow the product. Thus, little pressure will be exerted against the tooth surface under the gums again leading to poor cleaning in critical areas.
There is therefore a need for improved products and methods for enhancing the dental hygiene of a pet.